The present invention relates to a display device, and more particularly, to a technique effectively applied to a large-area display device having a backlighting arrangement such as a liquid crystal TV set.
Heretofore, liquid crystal displays have been available as display devices for displaying images.
The liquid crystal displays have been widely used as liquid crystal displays for liquid crystal TV sets and for personal computers (PCs) in recent years. In these years, such display devices have become increased in size.
When images are displayed on the liquid crystal displays, light sources are necessary. For example, a backlighting arrangement using fluorescent lamps such as cold cathode tubes or hot cathode tubes is mounted behind a liquid crystal display panel. The backlighting arrangement is an illuminating device having one or more fluorescent lamps disposed, for example, above a reflective plate, and an optical member such as a diffusive plate is disposed above the fluorescent lamps. In this backlighting arrangement, light emanating from the fluorescent lamps and directed toward the liquid crystal display panel is transmitted to the optical member such as the diffusive plate directly or after being reflected by the reflective plate. The optical member makes a flat panel-like form of light rays with less brightness uniformity. The light rays are then transmitted through the liquid crystal display panel.
In recent years, a structure using an optical transmitter has been proposed as one type of the backlighting arrangement (see, for example, patent reference 1). In the backlighting arrangement using the optical transmitter, this transmitter is disposed, for example, behind the liquid crystal display panel. Light sources such as the aforementioned fluorescent lamps are placed at an end of the optical transmitter.
[Patent reference 1] JP-A-6-230376
Of the above-described liquid crystal displays, in the display device having the optical member such as the diffusive plate disposed between the liquid crystal display panel and the light sources, the optical member is placed and held parallel to the liquid crystal display panel. The liquid crystal display panel, the optical member, and the light sources are held together by frame members. Since the liquid crystal panel and the optical member are held at their respective ends by the frame members, they swing when vibrations are applied. Especially, the optical member such as the diffusive member easily swings. Swinging motion of the optical member due to vibrations is produced in the direction in which the liquid crystal display panel and the optical member are disposed and so if vibrations are applied to the liquid crystal display device, the optical member may touch the liquid crystal display panel.
Normally, polarizers are stuck to both faces of the liquid crystal display panel to enhance the contrast. Therefore, if the optical member swings due to vibrations, and if the optical member touches the polarizers, scratching them, the contrast deteriorates in these scratched portions. This presents the problem that the image quality deteriorates.